In August IHS Markit posted a report titled “Apple may introduce LTPO TFT backplanes for iPhones to prolong battery life.” The only thing that the report got wrong was that Apple was preparing to use their patent-pending technology exclusively on Apple Watch 4 and not the iPhone. On one of Apple`s marketing pages they shout out the fact that their all-new Apple Watch 4 display uses LTPO technology as noted in the graphic below.
The IHS Markit report listed three Apple patents that covered this technology without providing any patent numbers. With a little digging we were able to find the three patents. With Apple adopting this technology for Apple Watch 4, these patents are now patents fulfilled. If you’re interested in learning more about this new technology, links to each patent are provided for you below:
(1) 20150053935: Organic Light-Emitting Diode Displays With Semiconducting-Oxide and Silicon Thin-Film Transistors (FIG. 7 above from this patent)
(2) 20180061867: Methods of Protecting Semiconductor Oxide Channel in Hybrid TFG Process Flow
(3) 20150055051: Display With Silicon and Semiconducting Oxide Thin-Film Transistors
The IHS Markit report had singled out a single patent figure for their report, patent FIG.7 from Apple’s patent 20150055051 that presents an example of an LTPO display. Below you’ll find their original image with our cleaner image below it for your review.
The IHS report importantly noted: “In the diagram, we can see that the backplane includes both the polysilicon (LTPS TFT) and the IGZO (Indium Gallium Zinc Oxide), otherwise known as Oxide TFT. Basically, LTPO equals to Low Temperature Polycrystalline Oxide. The pixel circuit would be patterned such that the switching TFT would be p-Si and the drive TFT would be IGZO.”
The report further noted that there were several possible reasons for why Apple chose to introduce LTPO:
To be more closely involved in flexible OLED component cost and technology
To reduce power consumption of Apple products
To achieve high electron mobility for higher resolution of its displays
To better manage its display supply chain and that of its partner-display manufacturers
For more on this, read the full IHS report that was published in August here. While today`s report has focused on Apple`s actual use of LTPO for Apple Watch 4, the IHS report also discusses the cons of using this technology in iPhones at this point in time that may interest some of you.
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